circulatory system

10 videos

1 skill

3B: With every beat, the heart pumps blood throughout the body through an intricate system of blood vessels to provide oxygenation to tissues - from about 4 weeks after conception until the day you die. Over your lifetime, it will pump about 175 million liters of blood (that’s only the amount of water that falls over the Niagara in a few minutes). This little pump in the middle of your chest is only the size of a clenched fist (if you’re an adult), and yet it does so much.

Take a closer look at the heart, explore some of its interesting features and get to know the three layers that make up the heart. Rishi is a pediatric infectious disease physician and works at Khan Academy.

Ever wonder why the heart sounds the way that it does? Opening and closing of heart valves makes the heart rhythm come alive with its lub dub beats... Rishi is a pediatric infectious disease physician and works at Khan Academy.

Remember the 3 key layers of a blood vessel (Tunica intima, Tunica media, and Tunica externa) and how arteries, veins, and capillaries are all different from one another. Rishi is a pediatric infectious disease physician and works at Khan ...